Maybe I can't see it because the phrase is already in my head buy what exactly is incorrect about "You have got mail?".
Is it just the superfluous 'got'?
Is it just the superfluous 'got'?
But, like "idonethis", and like you, we thought our version was just.. stickier. And it stuck.
Downvoter, this was my point: Sticky beats grammar. (See also: Think Different.) Sorry if I was too terse to make it clear.